Is the virtual homologation for pedestrian protection viable?

One out of five deceased in traffic accidents is a pedestrian. In addition, pedestrians represent the 20 % of the hospitalized injured people. The deadliness rate of a pedestrian crash is significantly greater than for the rest of accidents. Thus, pedestrian crash is one of the more lethal traffic accidents and, consequently, pedestrians are the most vulnerable road users. Vehicle's design can influence immensely in the risk of seriousness of the accident. Regulations are the legal instruments in order to establish if a vehicle achieves the minimum safety requirements. Nevertheless, homologation implies costly and destructive tests. This problem could be solved by simulation techniques. Analyzing the viability of a virtual homologation is the main goal of this article. After studying pedestrian crash biomechanics, virtual tests will be performed using Finite Element software (Ls-Dyna) to assess the influence of the design of vehicle and the effect of a safety system (active bonnet). Comparison between virtual tests results and real tests allows deducing if the virtual homologation for pedestrian protection is viable

Material characterization for FEM simulation of sheet metal stamping processes

Sheet metal forming is an important technology in manufacturing, especially in the automotive industry. Today, engineering simulation tools based on the finite elements method are employed regularly in the design of stamping dies for sheet metal parts. However, a bad material model choice or the use of nonaccurate enough parameters can lead to imprecise simulation results. This work uses ANSYS LS-DYNA software to analyze several material models and the influence of their parameter values in FEM simulation results. The main tool to solve these problems is an application designed to assist die stamp designers. The program allows a procedure to be defined to obtain the values of the properties of an unknown material, which combines finite element simulations with real experimental results. Results obtained for the simulation of a real automotive part are analyzed and compared with the real experimental results. Parameters involved in each material model have been identified, and their influence in final results has been quantified. This is very useful to fit material properties in other simulations. This paper fulfils an identified need in the manufacturing industry. In fact, the proposed application is currently being used by a manufacturer of automotive components

Aproximación del alumno al diseño por ordenador de conjuntos mecánicos reales

Proyecto de Innovación Docente en la asignatura Diseño Asistido por ComputadorEste Proyecto de Innovación Docente ha sido llevado a cabo en el curso académico 2004-05con los alumnos de la asignatura de“Diseño Asistido por Computador” de 2º de IngenieríaTécnica Industrial (Mecánica), que se imparte en el primer cuatrimestre. En él se ha inducido alos alumnos al trabajo en grupo sobre un problema de modelado virtual de un conjunto mecánico real, para el que es necesarioaprender y aplicar las herramientas básicas propiasde la asignatura. Además, el alumno puede, como ha ocurrido en muchos casos, profundizar de forma autodidacta en el empleo de algunas herramientas derivadas que por su complejidad o extensión, no se desarrollan en el marco teórico de la asignatura. La consecución de este doble objetivo ha supuestoun acercamiento al crédito europeo ECTS, basado en el trabajorealizado por el estudiante en su proceso de aprendizaje. El análisis de losresultados académicos y de las encuestas realizadas a los alumnos tras la experiencia, permiten emitir una valoración positiva de la metodología docente propuesta

Determining the stress distribution in a bicycle crank under in-service loads

New techniques have been introduced in the design process of most of the components of a bicycle. One of the main purposes of this introduction is trying to achieve the best weight/rigidity relation. However, all these advances have to take into account the security of the rider. Unexpected failures of some components such as stem, handlebar, or cranks, can cause serious injuries to cyclists and have to be prevented. Standard EN 14781:2006 establishes the safety and performance requirements that every bicycle and every component must fit from the point of view of fatigue failure. In this work, several bicycles cranks will be experimentally tested under the loading conditions of the reference standard. The stresses on the critical points will be analyzed to determine the influence of any variation in the test conditions. According to obtained data, several changes in the conditions of the standard will be proposed. Also, loading tolerance values for the test will be suggested, because they are not established in the standard

Validation and improvement of a bicycle crank arm based in numerical simulation and uncertainty quantification

In this study, a finite element model of a bicycle crank arm are compared to experimental results. The structural integrity of the crank arm was analyzed in a universal dynamic test bench. The instrumentation used has allowed us to know the fatigue behavior of the component tested. For this, the prototype was instrumented with three rectangular strain gauge rosettes bonded in areas where failure was expected. With the measurements made by strain gauges and the forces registers from the load cell used, it has been possible to determine the state of the stresses for different loads and boundary conditions, which has subsequently been compared with a finite element model. The simulations show a good agreement with the experimental results, when the potential sources of uncertainties are considered in the validation process. This analysis allowed us to improve the original design, reducing its weight by 15%. The study allows us to identify the manufacturing process that requires the best metrological control to avoid premature crank failure. Finally, the numerical fatigue analysis carried out allows us to conclude that the new crank arm can satisfy the structural performance demanded by the international bicycle standard. Additionally, it can be suggested to the standard to include the verification that no permanent deformations have occurred in the crank arm during the fatigue test. It has been observed that, in some cases this bicycle component fulfils the minimum safety requirements, but presents areas with plastic strains, which if not taken into account can increase the risk of injury for the cyclist due to unexpected failure of the component

New Procedure for the Kinematic and Power Analysis of Cyclists in Indoor Training

This article belongs to the Special Issue Sensor Technology for Sports Science.In this research, the performance and movements of amateur and professional cyclists were analyzed. For this, reflective markers have been used on different parts of the body of the participants in conjunction with sports cameras and a mobile power meter. The trajectories of the markers have been obtained with the software Kinovea and subsequently analyzed using error ellipses. It is demonstrated that the error ellipses help determine movement patterns in the knees, back, and hip. The covariance of the error ellipses can be indicative of the alignment and symmetry of the frontal movement of the knees. In addition, it allows verifying the alignment of the spine and the symmetry of the hip. Finally, it is shown that it is necessary to consider the uncertainty of the power devices since it considerably affects the evaluation of the cyclists’ performance. Devices with high uncertainty will demand a greater effort from the cyclist to meet the power required in the endurance test developed. The statistical magnitudes considered help to analyze power and evaluate the cyclists’ performance

Educational Resources for Self-learning of Descriptive Geometry

Proceeding of: 2nd International Symposium on the Education and Mechanism and Machine Science (ISEMMS 2017), 23-24 November 2017, Leganés, Madrid.In this work, two educational resources for self-learning of Descriptive Geometry are presented: the “Zero Course” and the “Support Course”. The creation of this e-learning material responds to the need that our students at University Carlos III de Madrid have to reach a minimum level at the beginning (Zero Course), and during (Support Course) the first course on technical drawing. First, the need is made out through results of surveys carried out in previous years. Then, some e-learning applications are exposed, among which the most appropriate to the need are chosen. Finally, the designed courses are described including all the technical resources. The results of the surveys carried out on the students of these courses, as well as some statistics of their qualifications, are also presented.Publicad

Clinical, immunophenotypic, and molecular characteristics of well-differentiated systemic mastocytosis

[Background]: Well-differentiated systemic mastocytosis (WDSM) is a rare variant of systemic mastocytosis (SM) characterized by bone marrow (BM) infiltration by mature-appearing mast cells (MCs) often lacking exon 17 KIT mutations. Because of its rarity, the clinical and biological features of WDSM remain poorly defined. [Objective]: We sought to determine the clinical, biological, and molecular features of a cohort of 33 patients with mastocytosis in the skin in association with BM infiltration by well-differentiated MCs and to establish potential diagnostic criteria for WDSM. Methods Thirty-three patients with mastocytosis in the skin plus BM aggregates of round, fully granulated MCs lacking strong CD25 and CD2 expression in association with clonal MC features were studied. [Results]: Our cohort of patients showed female predominance (female/male ratio, 4:1) and childhood onset of the disease (91%) with frequent familial aggregation (39%). Skin involvement was heterogeneous, including maculopapular (82%), nodular (6%), and diffuse cutaneous (12%) mastocytosis. KIT mutations were detected in only 10 (30%) of 33 patients, including the KIT D816V (n = 5), K509I (n = 3), N819Y (n = 1), and I817V (n = 1) mutations. BM MCs displayed a unique immunophenotypic pattern consisting of increased light scatter features, overexpression of cytoplasmic carboxypeptidase, and aberrant expression of CD30, together with absent (79%) or low (21%) positivity for CD25, CD2, or both. Despite only 9 (27%) of 33 patients fulfilling the World Health Organization criteria for SM, our findings allowed us to establish the systemic nature of the disease, which fit with the definition of WDSM. [Conclusions]: WDSM represents a rare clinically and molecularly heterogeneous variant of SM that requires unique diagnostic criteria to avoid a misdiagnosis of cutaneous mastocytosis per current World Health Organization criteria.Supported by grants from Asociación Española de Mastocitosis, Madrid, Spain (grant AEDM 2014); Instituto de Salud Carlos III, FEDER, Ministry of Economy and Competitivity, Madrid, Spain (grant PI11/02399); Fundación Ramón Areces, Madrid, Spain (grant CIVP16A1806); and Novartis Farmacéutica, S.A., Spain. I. Alvarez-Twose has received research support from Novartis Farmacéutica, S.A., Spain. A. García-Montero has received research support from Fundacion Ramon Areces (grant no. CIVP16A1806) and ISCIII Ministerio de Economia y Competitividad (grant no. PI11/02399). A. Orfao has received research support from Fundacion Ramon Areces (grant no. CIVP16A1806).Peer Reviewe

Detection of the KIT D816V mutation in peripheral blood of systemic mastocytosis: diagnostic implications

Recent studies have found the KIT D816V mutation in peripheral blood of virtually all adult systemic mastocytosis patients once highly sensitive PCR techniques were used; thus, detection of the KIT D816V mutation in peripheral blood has been proposed to be included in the diagnostic work-up of systemic mastocytosis algorithms. However, the precise frequency of the mutation, the biological significance of peripheral blood-mutated cells and their potential association with involvement of bone marrow hematopoietic cells other than mast cells still remain to be investigated. Here, we determined the frequency of peripheral blood involvement by the KIT D816V mutation, as assessed by two highly sensitive PCR methods, and investigated its relationship with multilineage involvement of bone marrow hematopoiesis. Overall, our results confirmed the presence of the KIT D816V mutation in peripheral blood of most systemic mastocytosis cases (161/190; 85%)-with an increasing frequency from indolent systemic mastocytosis without skin lesions (29/44; 66%) to indolent systemic mastocytosis with skin involvement (124/135; 92%), and more aggressive disease subtypes (11/11; 100%)-as assessed by the allele-specific oligonucleotide-qPCR method, which was more sensitive (P<.0001) than the peptide nucleic acid-mediated PCR approach (84/190; 44%). Although the presence of the KIT mutation in peripheral blood, as assessed by the allele-specific oligonucleotide-qPCR technique, did not accurately predict for multilineage bone marrow involvement of hematopoiesis, the allele-specific oligonucleotide-qPCR allele burden and the peptide nucleic acid-mediated-PCR approach did. These results suggest that both methods provide clinically useful and complementary information through the identification and/or quantification of the KIT D816V mutation in peripheral blood of patients suspected of systemic mastocytosis.This work was supported in part by grants from the Fondo de Investigaciones Sanitarias (FIS; grant number PI11/02399, FEDER) and Red Temática de Investigación Cooperativa en Cancer (RTICC; grant number RD12/0036/0048, FEDER) of the Instituto deSalud Carlos III (Ministry of Economy and Competitivity, Madrid, Spain), from Fundacion Ramon Areces (Madrid, Spain; grant number CIVP16A1806) and from Ayudas a Proyectos de Investigación en Salud de la Fundación Mutua Madrileña 2014 and Asociación Española de Enfermos de Mastocitosis (AEDM 2014). The National DNA Bank is supported by grants from the Instituto de Salud Carlos III of the Ministerio de Economia y Competitividad of Spain (grand numbers PT13/0001/0037 and PT13/0010/ 0067, FEDER). AM was supported by RTICC.Peer Reviewe

KITD816V mutation in blood for the diagnostic screening of systemic mastocytosis and mast cell activation syndromes

[Background]: Current diagnostic algorithms for systemic mastocytosis (SM) rely on the detection of KITD816V in blood to trigger subsequent bone marrow (BM) investigations. [Methods]: Here, we correlated the KITD816V mutational status of paired blood and BM samples from 368 adults diagnosed with mast cell activation syndrome (MCAS) and mastocytosis and determined the potential utility of investigating KITD816V in genomic DNA from blood-purified myeloid cell populations to increase diagnostic sensitivity. In a subset of 69 patients, we further evaluated the kinetics of the KITD816V cell burden during follow-up and its association with disease outcome. [Results]: Our results showed a high correlation (P < .0001) between the KITD816V mutation burden in blood and BM (74% concordant samples), but with a lower mean of KITD816V-mutated cells in blood (P = .0004) and a high rate of discordant BM+/blood− samples particularly among clonal MCAS (73%) and BM mastocytosis (51%), but also in cutaneous mastocytosis (9%), indolent SM (15%), and well-differentiated variants of indolent SM (7%). Purification of different compartments of blood-derived myeloid cells was done in 28 patients who were BM mast cell (MC)+/blood− for KITD816V, revealing KITD816V-mutated eosinophils (56%), basophils (25%), neutrophils (29%), and/or monocytes (31%) in most (61%) patients. Prognostically, the presence of ≥3.5% KITD816V-mutated cells (P < .0001) and an unstable KITD816V mutation cell burden (P < .0001) in blood and/or BM were both associated with a significantly shortened progression-free survival (PFS). [Conclusions]: These results confirm the high specificity but limited sensitivity of KITD816V analysis in whole blood for the diagnostic screening of SM and other primary MCAS, which might be overcome by assessing the mutation in blood-purified myeloid cell populations.This work was supported by grants from the Fundación Española de Mastocitosis (Madrid, Spain; grant number: FEM2021-SAM) and Blueprint Medicines Corporation (Cambridge, MA). PNN was supported by a grant of Government of Castilla y León (Orden EDU 875 2021), Spain; co-financed with the European Social Fund (BDNS (Identif.): 540787). We also thank the Agencia Estatal de Investigación (AEI) and European Regional Development Fund (FEDER) for the grant (EQC2019-005419-P) within the Subprograma Estatal de Infraestructuras de Investigación y Equipamiento Científico Técnico de 2019